The present invention relates to a solid cosmetic composition in the form of a molded powder cake comprising as a principal particulate charge hollow microspheres having one or more open or closed cavities.
The invention also concerns a process for producing such a molded powder cake.
It is known that certain makeup products in the form of solid powder cosmetic products, such as eyelid makeup or cheek makeup are generally provided in the form of molded powder cakes. A xe2x80x9cmolded powder cakexe2x80x9d is one which is produced by mixing a solid particulate phase and a binding agent (generally a fatty phase) in a solvent, so as to obtain a fluid paste, distributing the said fluid paste by pouring it into appropriate containers (dishes or cups) and then evaporating the solvent. The advantages of molded powder cakes are on the one hand the possibility of introducing various ingredients into the composition owing to the choice of the solvent selected, and on the other hand, the free choice of the form and material of the cup or dish, which permits multiple presentations of the final products.
In the preparation of molded powder cakes, several kinds of disadvantages are observed: a shrinkage phenomenon which results in the cup or dish not being completely filled (which is discouraging to the consumer); an irregular appearance of the surface of the product (a grooved, cracked or cratered appearance at the time of evaporation); and formation of a film of the binding agent on the surface.
Various solutions have been proposed to remedy these disadvantages.
In EP patent application No. 0038645, the cup, the open upper portion of which is fitted with a removable lid, is filled, in inverse position, by the base which is constituted by a support in the form of a grid. After evaporation of the solvent, the base is sealed with an appropriate base plate. In this manner, the irregular appearance of the surface through which is produced the evaporation of the solvent, as well as the shrinkage phenomenon, are not visible to the consumer. This procedure exhibits the disadvantage of requiring a special cup with the base support in the form of a grid.
U.S. Pat. No. 4,804,538 envisages the use of a cup the base of which has openings for filling with the fluid paste through the base, in non-inverse position, using injection nozzles fed under pressure, while the solvent is evaporated through the upper portion of the cup linked to a vacuum pump. This procedure requires complex and costly equipment.
In EP patent application No. 0165137 there is proposed the use of, as a binder, a bentonite treated with a cationic surfactant. Since this binder is not soluble in the solvent, the formulation of a surface film of the binding agent is avoided. However, the problem of shrinkage is not resolved and the feel of the resulting product is not satisfactory.
DE 332701 patent describes a process for preparing molded powder cakes in which the various operations of mixing the ingredients with an excess of solvent, molding and evaporation of solvent are effected hot increase the production costs. According to this patent, the condition of the surface of the molded powder cake is improved. However, the shrinkage phenomenon is not avoided.
It has now been discovered that the addition, as a constituent of the particulate charge, of a small weight amount of hollow microspheres having one or more open or closed cavities, permits the preparation, with a significant reduction of the shrinkage phenomenon, of molded powder cakes having a satisfactory surface condition and disintegration.
It has also been evidenced that the use of these novel constituents of the particulate charge permits the preparation at a moderate temperature and with a choice of various solvents, which indeed provides advantages on the economic level.
The invention thus relates to a solid cosmetic composition in the form of a molded powder cake constituted by a solid particulate phase and optionally a binder agent and conventional additives, wherein the particulate phase includes hollow microspheres having one or more open or closed cavities.
It has been noted that by practicing the invention a solid powder having a satisfactory surface condition and disintegration and a very small amount of shrinkage can be obtained. It will be noted here, as is well known to the specialists, that molded powder cakes have the appearance and the properties of a coherent solid product, having principally a defined surface as opposed to free powders (free flowing). Since it is a question of coherent solid products, their use requires the removal of a certain amount of powder by disintegration using an appropriate applicator.
The microspheres employed here are particles of essentially spherical form having generally a diameter less than 70 xcexcm (preferably less than 40 xcexcm).
The microspheres are produced from any appropriate inorganic or organic material, compatible with a use on the skin, that is, nonirritating and nontoxic.
The microspheres of an organic polymer material possessing a single closed cavity containing a gas, such as a hydrocarbon (for example, isobutane), can be prepared in accordance with known procedures, for example, those described in U.S. Pat. No. 3,615,972 and in EP patent application 0056219.
The organic microspheres are produced, for example, from polymers or copolymers derived from acids, amides or esters (monomers) having ethylenic unsaturation, from urea-formaldehyde polymers, from polymers or copolymers of vinylidene chloride, etc.
Mention can be made, as an example, of microspheres made from acrylate or methyl methacrylate polymers or copolymers, or even from vinylidene chloride/acrylonitrile copolymers.
Representative vinylidene chloride/acrylonitrile copolymers include principally those which contain, by weight, from 20 to 60 percent of units derived from vinylidene chloride, from 20 to 60 weight percent of units derived from acrylonitrile and from 0 to 40 weight percent of other units such as units derived from an acrylic or styrene monomer.
There can even be used crosslinked acrylic polymers or copolymers, for example, polymers the carboxylic groups of which are partially esterified with diols serving as crosslinking agents.
These materials can serve as a base for the preparation of microporous microspheres.
When the hollow microspheres employed in accordance with the invention are microporous microspheres, their range corresponds, for example, to a specific surface of at least 0.5 m2/g, and in particular of at least 1 m2/g. There is no upper limit (other than that resulting from the possibility of practical production of the microspheres having a very high porosity) for the specific surface. The specific surface can extend, for example, to 1000 m2/g or even higher, for example, up to a few hundreds of thousands of m2/g.
Particularly preferred are principally the microporous microspheres sold by Dow Corning under the trade name xe2x80x9cPOLYTRAP Q5-6603xe2x80x9d, or those sold by Seppic under the trade name xe2x80x9cMICROPEARL Mxe2x80x9d or xe2x80x9cMICROPEARL M100xe2x80x9d, as well as hollow microspheres having a closed cavity sold under the trade name xe2x80x9cEXPANCELxe2x80x9d by Kemanord Plast.
Representative microspheres derived from an inorganic material, include, for instance, silica microspheres having open porosity or, preferably, hollow, such as for example those sold under the trade name xe2x80x9cSILICA BEADS S700xe2x80x9d by Miyoshi Kasei Inc.
Preferably, microspheres having a density (more exactly a volume mass) lower than 0.7 g/cm3, for example between 0.01 and 0.7 g/cm3 are employed. The volume mass of the powders depend on their degree of packing. The volume masses given here correspond to the volume mass measured in accordance with the German standard DIN 53194, after ten packings.
The weight amount of the hollow microspheres in the molded powder cake ranges generally from 0.2 to 15 percent relative to the total weight of the composition with the solvent (fluid paste).
Concerning the amount of the hollow microspheres in the dried final composition, it can vary generally from 0.1 to 50 percent, preferably from 0.5 to 15 percent relative to the total weight of the composition after evaporation of the solvent.
The composition in the form of a molded powder cake containing the above defined microspheres can also contain pigments and/or other complementary charges. It is a question indeed of nonhollow particulate particles (in other words, those which essentially do not have any open or closed cavities), the dimension of which does not exceed about 200 xcexcm.
The complementary pigments and/or charges are those conventionally employed in cosmetic compositions in the form of solid powders. The pigments are selected principally from mineral pigments, organic pigments or their mixtures.
Representative mineral pigments include, for example:
titanium dioxide (rutile or anatase) optionally surface treated and listed in Color Index under the reference CI 77891;
black, yellow, red and brown iron oxides, listed under references CI 77499, 77492 and 77491;
manganese violet (CI 77742);
ultramarine blue (CI 77007);
hydrated chromium oxide (CI 77289) and
ferric blue (CI 77510).
Representative organic pigments, include, in particular, the following pigments:
DandC Red No. 19 (CI 45170);
DandC Red No. 9 (CI 15585);
DandC Red No. 21 (CI 45380);
DandC Orange No. 4 (CI 15510);
DandC Orange No. 5 (CI 45370);
DandC Red No. 27 (CI 45410);
DandC Red No. 13 (CI 15630);
DandC Red No. 7 (CI 15850-1);
DandC Red No. 6 (CI 15850-2);
DandC Yellow No. 5 (CI 19140);
DandC Red No. 36 (CI 12085);
DandC Orange No. 10 (CI 45425);
DandC Yellow No. 6 (CI 15985);
DandC Red No. 30 (CI 73360);
DandC Red No. 3 (CI 45430);
Carbon black (CI 77266); and
carmine or cochineal based lakes (CI 75470).
Nacreous pigments can also be employed and can be selected principally from
white nacreous pigments, such as mica coated with titanium oxide, bismuth oxychloride; and
colored nacreous pigments, such as mica titanium with iron oxides, mica titanium with ferric blue, or chrome oxide, mica titanium with an organic pigment of the above mentioned type, as well as those based on bismuth oxychloride.
The pigment can represent up to 50 weight percent of the total weight of the fluid paste.
The complementary charges are selected principally from:
talc, which is hydrated magnesium silicate, employed in particulate form, generally having a size lower than 40 xcexcm; the talc possesses humidity absorbing properties and is employed especially because of its unctuous feel or touch;
micas, which are alumino silicates of various compositions, which are provided in the form of flakes having a size ranging from 2 to 200 xcexcm, preferably from 5 to 70 xcexcm and a thickness of 0.1 to 5 xcexcm, preferably 0.2 to 3 xcexcm. The micas can be of natural origin (for example, muscovite, margarite, roscoelithe, lepidolithe, biotite) or of synthetic origin. The micas are generally transparent and permit to confer to the skin a satiny appearance;
starch, in particular rice starch;
kaolin, which is a hydrated aluminum silicate, which is provided in the form of particles of isotrope form having a size generally lower than 30 Am, and which possesses good fatty body absorption properties;
oxides of zinc and titanium, generally employed in particulate form having a size not exceeding a few micrometers (or even lower than 1 xcexcm in the case of titanium oxide); these oxides have an unctuous feel or touch, have good covering power and have a significant opacity;
precipitated calcium carbonate which, in the form of particles having a size lower than 10 xcexcm, have an unctuous touch and permit to obtain a matte appearance;
magnesium carbonate or bicarbonate which possesses, principally, perfume fixation properties;
metallic soaps derived from an organic carboxylic acid having from 8 to 22 carbon atoms, preferably from 12 to 18 carbon atoms, for example, zinc stearate, magnesium stearate, lithium stearate, zinc laurate, magnesium myristate and the like. These soaps, generally provided in the form of particles having a size lower than 10 xcexcm have an unctuous feel or touch and facilitate the adherence of the powder to the skin;
synthetic polymeric powders, such as polyethylene, polyesters (for example, polyethylene isophthalate or polyethylene terephthalate), polyamides under the form of particles having a size lower than 50 xcexcm, which possess absorbent properties, and permit to impart to the skin a velvety appearance.
These complementary charges can represent up to 65 weight percent of the total weight of the fluid paste.
The nonaqueous liquid vehicle (generally called xe2x80x9csolventxe2x80x9d) employed to suspend the various constituents can be selected, for example, from the group constituted by: alcohols (such as ethanol or isopropanol); straight or branched chain alkanes such as hexane, pentane, heptane or isoparaffin; the cyclic alkanes (such as cyclohexane); volatile silicones (for example, the cyclodimethicones); chlorinated solvents (such as dichloromethane or dichloroethane); and their mixtures. This solvent represents 30 to 70 weight percent of the fluid paste, and preferably 45 to 65 weight percent.
Preferably, as mentioned above, the suspension contains a fatty or oily phase which can act as a binder. This fatty phase is constituted by at least one fatty body, liquid or solid at ambient temperature and/or at least one oil soluble synthetic polymer the use of which in cosmetics is known.
Representative fatty bodies, liquid at ambient temperature, include mineral, animal, vegetable or synthetic oils, or even silicone oils. It is a question, for example, of petrolatum oil, liquid lanolin, arara oil, sesame oil, macadamia oil or jojoba oil and synthetic triglycerides.
Representative oil soluble synthetic polymers, include polyvinylpyrrolidone/hexadecene or PVP/eicosene copolymers such as the products sold by GAF Corp. under the trade names xe2x80x9cGANEX V-216xe2x80x9d and xe2x80x9cGANEX V-220xe2x80x9d.
The fatty phase generally represents from 0 to 20 percent by weight relative to the total weight of the fluid paste.
Various other additives can be introduced into the fluid paste, such as: sunscreen agents; softening agents; hydrating agents (sorbitol, glycerine); cicatrisive agents; anti-free radical agents; vitamins, perfumes and the like.
Finally, water-soluble consistency agents such as natural or synthetic gums, cellulose derivatives or acrylic polymers can be added during the course of preparing the fluid paste.
The cosmetic composition of the invention is prepared by a process comprising dispersing in a nonaqueous liquid vehicle a particulate phase and optionally a binding agent and conventional additives so as to obtain a homogeneous fluid paste, distributing the said fluid paste into appropriate containers, and evaporating the said liquid vehicle, wherein the said particulate phase includes hollow microspheres having one or more open or closed cavities.
The process of the invention comprises then, in a first stage, introducing the various constituents in a liquid vehicle. To suspend the various constituents of the cosmetic product in this solvent, it is possible to previously mix the powder constituents among themselves and the constituents of the fatty phase between themselves. However it is also possible to introduce the various constituents into the solvent in any order. The mixture is then homogenized generally at ambient temperature. This mixture is then directly molded in cups, preferably at ambient temperature. Finally the solvent is evaporated. To do so the cups are placed in an oven, preferably at a temperature not exceeding about 40xc2x0 C., for a time sufficient which can vary from 6 to 60 hours.